Tuesday 18 April 2017

Why are Portugal's Pines and Palms Dying?

Portugal’s Palm and Pine Trees are under attack
Dead Pine (Photo: Steve Andrews)

As you travel around in Portugal you can’t hope but notice the dead palms and dead and dying pine trees, but what is causing this disaster? It is a combination of drought, disease, and in the case of the pines, because of a tiny nematode worm and species of beetles that transport it. The pines and palms of Portugal are under attack. Let’s take a look at the two problems, starting with the pines.

Male Pine Wilt Nematode (Photo: A. Steven Munson, USDA Forest Service, Bugwood.org)

Pine trees, which are a very common tree in the forests of Portugal, are under threat from a very tiny worm known as the pine wilt nematode (Bursaphelenchus xylophilus), which causes “pine wilt,” as well as from a fungus known to science as Fusarium circinatum, which causes pitch canker disease. The worm’s name is often abbreviated to the letters PWN.

The nematode worms are spread to healthy trees by bark beetles and wood borer beetles that have become infested with the worms in a dead and decaying tree. After a tree is infected the needles become brown and the tree can die within a matter of months. The early stage of this nematode does not feed directly on the pinewood but on fungi in the decaying wood. Once the worm is in a healthy tree it feeds within the resin canals and spreads throughout the roots, trunk and branches. It reproduces rapidly in summer. It first caused terrible and noticeable tree loss in Japan in 1905, but is found in and has spread in many other parts of the world, including America, Canada, Mexico, China and Korea. In Europe it has become a problem in Portugal, and there are serious concerns that it could spread to other countries, including the UK, where it would be a threat to the Scots pine (Pinus sylvestris).

Monochamus galloprovincialis (Photo: Siga)

In Europe, the pine wilt nematode is known to be spread by the Timberman Beetle (Monochamus galloprovincialis). In Japan the epidemics have been particularly bad in hot, dry summers, and the problem appears to be spreading in drought conditions experienced in Portugal. Drought weakens the trees and they become prone to attack by beetles.

I have become alerted to the pine wood nematode by witnessing the dead and dying pines near where I live in the Quinta do Conde area. The authorities here are chopping the trees down and then cutting up the trunks in an effort to deal with this threat to the forests. The wood can be fumigated or kiln-dried to kill the worms and beetles or it can be burned or chipped.

Infected pines (Photo: Steve Andrews)

Some species of pine appear to be more resistant to attacks by PWN than others. This can be seen in forests where there are stands of dead trees and others surviving.

Red Palm Weevil

Destroyed Palm Crown (Photo: Kuchenkraut)

The threat to the palms of Portugal, and to those in many other countries around the world, is being caused by an insect known as the Red Palm Weevil (Rhynchophorus ferrugineus). The grub of this weevil eats the crown of the tree and burrows into the palm trunks making a long tunnel and killing its host as it does so. The adult insects are quite attractive and large, reaching a size of between 2 and 4cm.

Red Palm Weevil (Photo: Luigi Barraco)

The females lay their eggs on palms, especially in the crowns, and on recently pruned leaf scars and in lesions in the trunks. They can lay as many as 500 in total and an infestation of these weevil larvae will kill the host palm. After eating their fill the grubs pupate in a cocoon they weave of palm fibres and usually make in leaf litter.

The insects attack many species of palm, although a favourite for this weevil is the Canary Date Palm (Phoenix canariensis), a very popular ornamental palm that is frequently planted in gardens, parks and in city streets and squares. The Date Palm (P. dactylifera) is also a victim of this pest. Fortunately the Washingtonia palms seem to be resistant to attacks by the insect. The weevils can fly and this is how they invade new territory but they can also be transported in infested palms.

In Portugal, most of damage caused by Red Palm Weevils has taken place in the Algarve and south of the country, but over the years this insect pest has spread to other parts as well. In the heart of Lisbon you will see what’s left of palms that have been killed by the Red Palm Weevil.

In some parts of the world, including Borneo, Vietnam and Indonesia, the grubs are regarded as a delicacy, and are eaten alive or cooked. In countries, like Spain and Portugal, they are a very serious problem that are destroying ornamental palms.

There are various ways of treating infested palms, and insecticides injected into the trunk is a method that has often been used. It is possible to save palms under attack by these insects but often the damage has become to severe and a very beautiful tree will die and get removed.

Both palms and pines add to the beauty of Portugal and it would be tragic if they were lost from many parts of the country.

Thursday 13 April 2017

Why Common Swifts are no longer common

The Common Swift is not so common in the UK anymore
Common Swift (Photo: Justyna Baytel)

The common swift (Apus apus) was once an aptly named bird, so often seen screaming and screeching as it swooped and soared over our streets but this is no longer the case. The common swift is no longer common in the UK. My father Bill, who lives in Cardiff, used to keep a diary in which he recorded the dates the swifts arrived each year at the start of summer. He no longer bothers because no swifts arrive where he lives any more. He often rightly complains that these once common birds have vanished from the road he lives in.

The common swift's British breeding populations are known to have dropped drastically in numbers, and the RSPB have the bird on the "Amber List" for species in danger.

So where have all the swifts gone? What has happened to them and what can be done about it?

One of the main reasons for their serious decline is how houses are being built and maintained today. In old buildings the swifts used to nest under the eaves but now roofs are sealed and the birds cannot find any way of entering or anywhere to nest. Renovations to old houses are sealing the roofs too. Making the problem worse, is the fact that swifts like to return to buildings where they have nested before, and they are not keen on newly built housing. Demolition of old buildings demolishes the nesting sites used by swifts.

Swiftlets in nest box (Photo: Public Domain) 

Fortunately, there is a solution. Nest boxes can be placed on houses and buildings and access to roofs can be left by people who care about the conservation of these summer visitors. One group that is actively monitoring the swift population in the UK is aptly named Action For Swifts. It is reassuring to know that there are people all over Britain that are very concerned about this problem and who are taking action to try and do something about it before it is too late. I emailed a contact I found for Action For Swifts in the Cardiff area and was delighted to receive a reply from a lady called Julia. She confirmed what my Dad had been saying, that the situation for swifts in Cardiff is not good. But she informed me that there are a couple of known colonies in the suburbs of Canton and Cathays, and that Cardiff University is helping with conservation measures to help the common swift. The university has accepted advice on renovation work that is swift-friendly and has put up a large number of nest boxes on its halls of residence.

"Swift City"

Julia informed me that “Glamorgan Bird Club is also doing a variety of things, including raising awareness and has recently installed nest boxes in a church tower in the Vale.

And the RSPB is looking to make Cardiff a "swift city" - to work with the Council, house builders, etc, to increase nest sites, amongst other things.”

My father was very glad to hear this news and spread the word to a group of local radio amateurs he is friendly with. Obviously, the more people that know about the threat to the common swift and what steps can be taken to help them recover, the better it will be for these amazing birds.

Why Swifts are truly remarkable birds
Common swifts are truly incredible for many reasons. They have very short legs and because of this they are unhappy when landed because they are unable to walk. They use their short legs and feet to cling to vertical surfaces, such as the wall of a house. Because they do not land on the ground, the birds spend most of their lives on the wing and they even sleep when flying. Non-breeding young birds can spend as much as 10 months of a year in continuous flight. No other bird spends as much time on the wing.

Speaking of flight, swifts migrate all the way to and from equatorial Africa, all the way to the UK and many other parts of Europe and the Northern Hemisphere.

Swifts gather their nesting materials on the wing too, using feathers and small bits of vegetable matter that they find blowing about. They bond it together to make their nests using their saliva as an adhesive.

A remarkable bird, I am sure you will agree, so let’s do all we can to make the common swift, common again!

Tuesday 4 April 2017

Great Crested Newts in Heath Park Pond and the Flora and Fauna of Heath Park

Heath Park is a wonderful nature conservation area

Heath Park Second Pond (Photo: Steve Andrews)

Heath Park in Cardiff is a wonderful area for nature conservation and is home to a colony of the rare great crested newt (Triturus cristatus). The amphibians breed in the pond there that has been in the park for very many years.

Great Crested Newts

Those responsible for the park and pond’s upkeep have very wisely left dead tree-trunks around the edges of the pool and in the woodland that surrounds it.

Habitat created for Great Crested Newts (Photo: Steve Andrews)

Water plants, such as watercress (Nasturtium officinale) are enclosed in mesh so that they are protected and this creates a wonderful area for the newts to lay their eggs in and to hide. Great crested newt females wrap their eggs in the leaves of aquatic vegetation, as do other species of newt.

Aquatic plants (Photo: Steve Andrews)

An information board gives a lot of information about the great crested newt, including how far it travels away from water. The much smaller palmate newt (Lissotriton helveticus) also breeds in Heath Park Pond. This comes as no surprise to me because I used to have a girlfriend many years ago, who lived in the nearby King George V Drive that circles Heath Park, and these far commoner newts could be found in the garden pool of the house where she lived. On the info board, there are illustrations and notes about the other interesting species of wildlife that can be seen in the pond. The common frog (Rana temporia) is another amphibian that breeds here.

Info board (Photo: Steve Andrews)

Aquatic insects that use the Heath park Pond include the great diving beetle (Dytiscus marginalis), the water boatman (Notonecta glauca) and dragonfly and damselfly species. The great diving beetle and its larva hunt tadpoles, small newts, fish and worms. The larvae have large mandibles with which they grab their prey as they suck out the life-blood. Both adults and larvae will bite. The adult beetles fly by night to look for suitable stretches of freshwater. The water boatman or backswimmer can also fly. It is a predatory bug that feeds on mosquito larvae and other small water creatures. It gets its name from its habit of swimming upside down and using its legs as paddles to propel it through the water.

Alien and invasive species

Parrot's Feather

The information board includes a warning and request: the public are asked not to release species that are non-native and alien to this country. An example being species of terrapin that can be a danger to British wildlife. The species of water milfoil known as parrot’s feather (Myriophyllum aquaticum) is mentioned as an example of an invasive species, and it is pointed out that this particular plant caused a problem at Heath Park Pond where it grew abundantly and had to be carefully removed. It is a threat to British species because it grows so well that it displaces native plants.

Elsewhere in Heath Park

Elsewhere in Heath Park they have constructed a second pond near the golfing area. The information board explains that great crested newts do best in places where there are more than one pond, so that if one pond dries up in hot weather, for example, the amphibians can still breed in another. I don’t know if any newts are using it but it is certainly big enough and there were two mallard drakes swimming around on it.

Walking a dog to Heath Park Main Pond

There is quite a lot of woodland and areas which were once rough ground and scrub have been allowed to grow into thickets of small trees and bushes. There are plenty of great places for birds and other wildlife to live in the park. It is reported that the green woodpecker (Picus viridis) lives in this woodland, and I wouldn't be at all surprised because it is a great place for them.

Paths help you enjoy walking around the woodland and many people take their dogs for walks in Heath Park.

In the grassland and extensive lawns of Heath Park there are extensive colonies of lady’s smock or cuckooflower (Cardamine pratensis), which takes its name from its habit of flowering around the time when the first cuckoos could be expected to arrive in the UK.

Cuckoo Flowers (Photo: Steve Andrews)

It is of especial interest, and a useful plant when it comes to wildlife conservation, because it is one of the main food plants of the caterpillar of the orange tip butterfly (Anthocharis cardamines). This pretty species, with orange tips on the forewings of the males, has been increasing again in numbers in some parts of Britain, so anywhere that plants that its larvae feed on grow, is going to be helpful in ensuring this butterfly’s survival. The cuckoo flower used to be gathered as a substitute for watercress, and like the latter plant it likes to grow near water.

The abundance of lady’s smock plants in the park, as well as the natural woodland, and the obvious great attention that had been paid to making the ponds a suitable habitat for great crested newts and other aquatic wildlife, made me feel that Heath Park is one of the best parks in Cardiff for nature conservation.